1. Field of the Invention
The present invention generally relates to refrigerant charging apparatus. Certain embodiments relate to refrigerant charging and pressure testing assemblies useable to charge a refrigerant system (e.g., a motor vehicle refrigerant system).
2. Description of Related Art
One common technique for assessing the refrigerant charge of a refrigerant system (e.g., an automotive vehicle air conditioning system) is to check the pressure within the refrigerant system by coupling an end of a pressure gauge hose assembly to a service fitting portion of the refrigerant system (e.g., a low-pressure side fitting of the refrigerant system). The pressure gauge may be read, and the pressure gauge hose assembly may be removed from the refrigerant system. If the pressure gauge reading indicates that the refrigerant charge is below a desired level, a charging hose assembly may then be coupled to the refrigerant system, and refrigerant may be added to the refrigerant system through the charging hose assembly.
A first end of a charging hose assembly typically includes a coupling, which may be releasably coupled to the service fitting. A second end of the charging hose assembly typically includes a shutoff valve that may be secured to an outlet of a pressurized refrigerant container (e.g., a refrigerant can). During use, the charging hose assembly is coupled to the service fitting of the refrigerant system and the valve is opened to allow refrigerant to flow into the refrigerant system from the pressurized refrigerant container. After allowing some refrigerant to flow into the refrigerant system, the charging hose assembly may be removed from the service fitting. The pressure gauge hose assembly is again coupled to the service fitting to assess a refrigerant charge of the refrigerant system. After the refrigerant charge is assessed, the pressure gauge hose assembly may be removed from the refrigerant system.
If the refrigerant charge is below a desired level, the charging hose assembly may be reattached to the service fitting and more refrigerant may be added to the refrigerant system. The refrigerant charge may then be reassessed with the pressure gauge hose assembly. These steps may be repeated, using the separate hose assemblies, until the measured pressure within the refrigerant system indicates that the refrigerant system is adequately charged with refrigerant.
U.S. Pat. No. 6,609,385 to Ferris et al. and U.S. Patent Application Publication No. 20040079092 to Ferris et al., each of which is incorporated by reference as if fully set forth herein, disclose a refrigerant charging/pressure testing hose assembly that is useable to both check the pressure in a refrigerant system and, if necessary, add refrigerant to the refrigerant system. The assembly includes a refrigerant hose with a quick disconnect coupler at one end that is connectable to a service fitting of a refrigerant system, a piercing-type shutoff valve at the other end that is connectable to a refrigerant container, a pressure gauge coupled into an intermediate portion of the hose, and a check valve in the hose between the shutoff valve and the pressure gauge.
Some manifold assemblies may also be used to pressure test and/or charge a refrigerant system. For example, QUEST™ brand part# 413 (available from EF Products, Inc., Dallas, Tex.) is an R-134a Manifold Gauge for use by professional service personnel. Part# 413 includes two pressure gauges. One pressure gauge may be coupled to the low-pressure side of a refrigerant system using a hose. The other pressure gauge may be coupled to the high-pressure side of the refrigerant system using a hose. Both of the gauges are coupled to handle-operated valves that open and close flow to the pressure gauges from the hoses. In the manifold, both pressure gauges and both hoses (i.e., the low-pressure side of the refrigerant system and the high-pressure side of the refrigerant system) are in fluid communication with a third hose that may be coupled to a refrigerant container (either a 30 lb. cylinder of refrigerant or, with an adapter, a refrigerant can). Thus, the refrigerant system may be charged through the low-pressure side or the high-pressure side of the refrigerant system. Charging of a refrigerant system through the high-pressure side of the refrigerant system may be dangerous and should only be performed by professional service personnel.